Analysis of surveillance and prevention plan for African Swine Fever in Italy in 2020

Abstract Background African Swine Fever (ASF) is a challenge for pig health worldwide. The disease has spread to multiple countries on five continents. ASF‐free countries need to apply effective strategies to prevent the introduction of infection. Methods Italy implemented a surveillance and prevention plan for ASF in 2020, supported by a dedicated information system. Several pillars for action have been identified: passive surveillance in both domestic pigs and wild boar populations, verification of the implementation of biosecurity measures on farms and an awareness campaign for all involved stakeholders. Results There were some regional differences in the management of passive surveillance. In order to identify all critical points and apply corrective measures, regional authorities were called to carry out a gap analysis exercise in July 2020. There were an adequate number of samples collected from wild boar but the number of samples collected from domestic pigs was below the target in most regions. Furthermore, sample distribution within the country was not homogeneous. Conclusions During the forthcoming year, some issues must be addressed in order to establish an effective early detection system in Italian ASF‐free regions.

transmitted, especially to wild boars, through abandoned human food waste (Farez & Morley, 1997;McKercher et al., 1978;Mebus et al., 1993;Mebus et al., 1997). For all these reasons, it is classified as a notifiable disease and listed in the Terrestrial Animal Health Code (OIE, 2019) and European Animal Health Law (AHL) (Regulation EU, 2016). ASF, originating on the African continent, reached Georgia in 2007, spread to the Asian continent, arrived in the European Union in 2014, in China in 2018, in Papua New Guinea and India in 2020 (Blome et al., 2020). Furthermore, the first ASF outbreak in the Americas in the last 40 years was reported in July and September 2021 in the Dominican Republic and Haiti (USDA, 2021a;USDA, 2021b). In the first half of 2021, ASF has been reported by the following European countries: Bulgaria, Estonia, Germany, Hungary, Italy (in the Sardinia Region only), Latvia, Lithuania, Moldova, Poland, Romania, Serbia, Slovakia and Ukraine (ADIS, 2021). Among these countries, Italy has experienced a peculiar situation because ASF has been present in the Sardinia Region since 1978, probably due to the introduction of contaminated food waste from the Iberian Peninsula (Laddomada et al., 2019), while the rest of the country is free of the disease.
In the Italian Peninsula, the risk of ASF introduction arises primarily from human factors related to contact with infected areas in different countries. The risk of importation from the Sardinian infected area is quite lower than the risk of importation from other countries because Sardinia is isolated from mainland Italy and rigorous controls at ports and airports, as well as application of regionalisation guidelines to pig products, protect ASF-free zones from ASF virus introduction. Moreover, in recent years the risk of infection on the island has decreased considerably, with evidence of viral circulation reduction during the past 2 years, after specific measures were implemented to reduce the prevalence of infection in the endemic area. So the risk of ASF introduction from Sardinia is lower than in the past .
Nevertheless, the introduction of contaminated food or materials transported by travellers is difficult to prevent, avoid, and, more importantly, is not predictable. For these reasons, in 2019, the Italian Ministry of Health, supported by the National Reference Laboratory for Swine Fevers (NRL), developed a surveillance plan to be implemented in 2020, with the aim of preventing the possible introduction of virus in the rest of the country through early detection of infection (Italian Ministry of Health, 2019). This plan was presented for the approval of the European Union Commission as a part of a more extensive document that included the annual ASF eradication plan for the Sardinia Region.
Therefore, the aim of this paper is to describe the implementation of the Italian surveillance and prevention plan in ASF-free territories, present the initial results and describe the gaps identified after the first year of its implementation. Regarding passive surveillance in wild boars, everyone is required to report discoveries of carcasses found in the field, and the local veterinary service collects samples from these animals (including wild boars killed in motor vehicle accidents). Wild boar sampling was planned in order to rule out ASF virus infection in the general wild boar population. The ASF plan includes the sampling of all wild boars found dead;

MATERIALS AND METHODS
in order to provide a number to be used as indicator in reporting, a minimum target of 600 samples is identified for the whole country.
Each Italian region is required to collect a certain number of samples, according to the wild boar population estimate in that territory, with the aim to find at least one positive sample in case of infection presence.
Each regional target represents in turn the minimum number of samples to be collected and tested. Anyway, of course, in case of reasonable suspicion of ASF based on the clinical signs, post mortem lesions, or epidemiological evidence (such as several dead wild boars found in the same area), the National Contingency Plan should be applied.
Regarding domestic pigs, any suspected case (such as mortality rate over 30%, presence of haemorrhagic clinical signs or lesions) must be notified to the competent authority, and the authority should apply the measures described in the specific contingency plan. Sampling for passive surveillance in domestic pigs was planned for all suspect cases and preferably for farms including less than 50 animals (family and backyard farms). In the absence of suspect cases, veterinary service is required to collect samples from at least two dead pigs per region and per week, in order to improve the sampling sensitivity.
Moreover, in order to include the rearing systems considered at major risk for the transmission of ASF due to their lower levels of biose- and is able to identify all known genotypes (King et al., 2003). A few laboratories chose to apply other protocols using commercial kits that complied with international standards.
NRL supports the Ministry of Health compiling periodic reports to verify the progress of surveillance activities for ASF and to manage any critical issues. A general activity check was conducted from June to September 2020, by engaging with regional authorities. The gap analysis approach was used to evaluate eventual gaps affecting surveillance activities and to identify corrective measures. Specifically, 20 regional working groups have been established, including regional veterinary authorities, that focused on the territory under their jurisdiction.
The whole process was planned in three stages. First, a virtual meeting was held, after the first semester of plan implementation, on June 2020. Ministry of Health described the aim of this verification activity and asked each regional delegation to conduct a gap analysis based on a standardised questionnaire. Then regional working groups carried out their assignments in three months. In order to perform the required activities, components of each group met as often as needed, and they could be supported by NRL in those occurrences more difficult to solve.
When completed, gap analysis results were evaluated by Ministry of Health and NRL for each region. Finally, a virtual meeting took place on September 2020 in order to give a feedback to working groups. So, based on gap analysis results, adequate measures were recommended by Ministry of Health in order to solve the identified regional gaps.
The questionnaire comprised five key sections about the implementation of the ASF plan: passive surveillance in wild boars, passive surveillance in domestic pigs, wildlife management procedures, implementation of biosecurity measures, and training activities. For each topic, the regional working groups were asked to provide the following information: -The current situation and optimal standards to be achieved -Identification of gaps between the current and the desired situation and of the measures to be applied -Evaluation and identification of the resources needed to fill the gaps identified -Identification of factors that could promote or limit performance of surveillance activities

RESULTS
The law orders were not yet ready at the beginning of 2020 and the official launch of the plan was delayed. In addition, the national database was implemented later than the official launch of the plan. demic, which could explain the low compliance with the plan, at least in the first part of the year. Moreover, different regional working groups approached the gap analysis exercise differently: for example, certain regions identified practical measures to address the gaps whereas other regional working groups experienced difficulty not only in identifying the gaps but also in solution-finding. Anyway, for each detected and discussed critical point, an appropriate action was recommended to fill the gap in that territory.

DISCUSSION
The Italian veterinary services have had the opportunity to get to know ASF very well. They have had longstanding experience because of the endemic situation in the Sardinia Region, which has required significant F I G U R E 3 Number of registered samples collected from domestic pigs (left) and wild boars (right) according to geographic location for Italian passive surveillance of African swine fever (2020). The data were extracted from the National Information System in February 2021 resources, particularly in recent years, to get closer to eradicating the infection and which still necessitates restrictions on the Sardinian swine sector effectively preventing its development .
Considering the evidence recorded over more than 40 years, the Italian and Sardinian authorities have demonstrated that they are able to effectively manage the risk of virus escape from Sardinia. There has been only one outbreak originating from Sardinia that occurred in 1983. It was notified and immediately eradicated (Danzetta et al., 2020).
At present, based on different conditions in Sardinian scenario rather than the European one (Laddomada et al., 2019;Loi et al., 2020;Mur et al., 2017), the threat of introduction of genotype II ASF virus from other countries in which ASF is endemic appears to be much more relevant, than the threat of outbreaks originating from Sardinia . Thus, all Italian regions are exposed to the risk of ASF outbreaks that would have devastating effects on local and national economies. A possible ban on the export of fresh and cured pork products is a particular concern. Italian pork products are in large demand worldwide and are of great economic importance, with potential for growth in the near future. Regarding the wild boar surveillance, most tested samples were related to road accidents. As these data were not officially recorded in 2020, it was established to insert the flag 'wild boar road killed' into the national database for 2021 and 2022 years. Nevertheless, the method of sampling wild boars needs further consideration because using samples collected following road accidents is a matter of debate (Jori et al., 2020).
Surveillance in domestic pigs was initially directed towards family and backyard farms, recognised as having the highest risk of exposure to the eventual introduction of the virus. However, family farms are intended for self-consumption: mortality rate is low and farmers do not communicate data about mortality events regularly to veterinary services. For this reason, in the plan, also commercial herds were considered as feasible to be sampled for surveillance purposes. The Italian Veterinary System hopes in this way to address the threat posed by ASF and to limit the damage of a possible future introduction of the infection in territories that are currently still ASF free.